Web worker does not have cache-control header

When I use fetch in javascript, the file has a cache-control header.

var StockFish='https://www.example.com/stockfish-16.1-single.js';
params={cache:'force-cache'};
try {await fetch(StockFish,params)} 

When I use a web worker, the file has no cache-control header.

stockfish=new Worker('https://www.example.com/stockfish-16.1-single.js')

Does anyone know why this happens?